Final answer:
To calculate the number of people in the concert hall when 55% of the seats are occupied, multiply the total number of seats by the percentage occupied.
Step-by-step explanation:
To calculate the number of people in the concert hall when 55% of the seats are occupied, we first calculate the number of seats that are occupied. We can do this by multiplying the total number of seats (1540) by the percentage occupied (55%).
Number of occupied seats = 1540 seats x 0.55 = 847 seats.
Therefore, when 55% of the seats are occupied, there are 847 people in the concert hall.